The present invention relates to a vehicle-control communication system for dividing controls to a plurality of devices incorporated in a vehicle into a plurality of prespecified control function units, detecting status information required for control over control function units for each of the plurality of control function units by a plurality of sensors, and controlling driving of a plurality of actuators as targets for control over the control function units according to the detected status information as well as to information from other control function units.
A plurality of processors for control have been incorporated in a vehicle to perform various types of vehicle control by using these processors for control. For example, a processor for engine control has been used for controlling the engine to compute an amount of fuel injection corresponding to a state how the engine is running and control fuel injection to the engine according to a result of the computation. In addition, each of controls such as transmission control, brake control, and auto-drive control is also realized by using each of the corresponding processors for control respectively.
By the way, the demands for vehicle control have been becoming more and more sophisticated in recent years. It is difficult to perform the advanced vehicle control only by discretely providing each of the vehicle controls independently, because it is necessary to exchange information between processors for various controls, namely between modules for various controls and to perform integrated vehicle control according to the exchanged information. In a vehicle-mounted communication unit disclosed in Japanese Patent Laid-Open Publication No. SHO 62-237895, for instance, advanced vehicle control is realized by connecting various control modules to each other using a communication unit such as a LAN, systematizing communications for vehicle controls, and providing integrated controls for various vehicle controls.
Each of the various control modules detects a status of the vehicle using sensors, subjects corrective computation if necessary according to the detected status of the vehicle, and controls driving of an actuator as a target for control. The number of sensors and number of actuators included into the various control modules has increased due to such an advanced control. Further, the number of control modules is also increasing in order to previously realize vehicle control functions not realized so far. As a result, when various control modules are connected to each other using the above mentioned communication unit for realizing multifunctional vehicle control without any consideration of the above mentioned matter, a number of communication lines and configuration of the unit sections related to communication processing required for realization thereof increase.
In order to overcome such a problem, in the electronic control system for a vehicle disclosed in Japanese Patent Laid-Open Publication No. HEI 4-114203, for example, a main control module that integrates a plurality of control modules into one is provided, a communication line is used for connection between the plurality of control modules and the main control module, and the main control module performs centralized management and control of the plurality of control modules in such a manner as if the main control module controls the other control modules as slave devices. Thus, this electronic control system for a vehicle can integrally control the various types of vehicle control and also perform multifunctional vehicle control.
However, during the development of vehicles in recent years, there have been increased cases where specifications of sensors and actuators of a control module are partially changed or specifications of operation processing are changed. In such cases, in the conventional type of vehicle-control communication system, it is required to design a new control module again because the system is constructed by control module units. This lowers the development efficiency.
In addition, there are cases where different control modules are combined or the way the control modules are used is different depending upon the type of vehicle. In such cases also, it is required to design a new control module again for each type of vehicle, which lowers the development efficiency.
Furthermore, in association with provision of many functions to the vehicle in recent years, there has been a tendency to increase the functions provided to each control module and perform the processing at higher-speed. Further, and also there have been tendencies that advanced throughput has been demanded for each of the control modules itself and the number of control modules to be incorporated in a vehicle has increased. Due to such reasons, an amount of information to be transmitted and received between control modules has increased. However, the conventional type of communication system in which all the control modules are connected to each other by a communication unit such as a LAN can not speedily support such an increase in an amount of information for communications. Further, in the conventional type of communication system in which a main control module is used so that the main module is followed by control modules to make them execute communications between the control modules, the load on the main control module increases. Thus, neither of the systems can sufficiently support an enormous amount of information transmitted and received within a multifunctional vehicle.
A unified communication system is constructed in the conventional type of the vehicle-control communication system. Therefore, if a malfunction occurs within a control module, there is now way for the other control modules to know this malfunction and they keep on performing the control operation. In order to overcome this redundancy, the system is so designed that each of the control modules discretely monitors the status of the system on its own. However, this increases a workload on the control modules.
Various types of vehicle-control communication system are developed by giving consideration to the multi-functioning of the vehicles. However, original information used for vehicle control may be tampered with due to incorporation of an illegal communication node in a vehicle or through communications by a maliciously-intended communication node in accordance with advanced control provided for a vehicle. Further, the information for vehicle control may be tapped via those illegal communication node or a maliciously-intended communication node. It has been desired to prevent the tampering with or tapping of information before it happens. In actual cases, when vehicles having the same or similar type of vehicle-control communication system incorporated therein come closer to each other, the various elements of information on the vehicle-control communication systems interfere with each other and cause unexpected malfunctions. It is also necessary to prevent a accidents due to the malfunctions described above before they happen.
It is an object of the present invention to provide, for the purpose of solving the problems described above, a vehicle-control communication system which can flexibly and easily support further system development with a small amount of labor and time for development even under the situations of an increased number of control modules, speeding up, partial changes in specifications for the control module, and increasing the amount of information for communications between control modules in association with achievement of higher performance of a vehicle, and which also can enhance development efficiency, as well as to obtain the vehicle-control communication system which can prevent tampering with or tapping of information transmitted and received within the system before it happens.
In the present invention, a plurality of control function units such as ECI (engine control) and ABS (anti-lock brake system) are divided into a plurality of control function groups; a plurality of I/O processing units execute, within each of the plurality of control function groups, processing that is of comparatively light load and requires real-time processing by a control function unit; and an operation processing unit executes processing requiring high-speed processing within each of the plurality of control function units such as execution of a plurality of operation processing corresponding to the plurality of control function units according to the information inputted from the plurality of I/O processing units and output of each result of the operation processing to the plurality of corresponding I/O processing units respectively; then, within each control function group, a plurality of I/O processing units are connected to an operation processing unit by a first communication unit, while the plurality of control function groups are connected to each other by a second communication unit so that hierarchical communications are realized such that transmit-receive of information within each of the control function groups is performed via the first communication unit and transmit-receive of information between the control function groups is performed via the second communication unit.
In the present invention, a first communication unit connects at least two or more of control function groups to each other, and between the connected control function groups, information to be transreceived between control function groups is also transmitted and received via this first communication unit.
In the present invention, a plurality of control function units are further divided into or integrated into a plurality of I/O processing units for executing input/output processing to sensors and actuators corresponding to the plurality of control function units by the plurality of control function units as well as into a plurality of operation processing units for dividing the plurality of control function units into a plurality of control function groups, executing a plurality of operation processes corresponding to the plurality of control function nits according to the information inputted from the plurality of I/O processing units at least belonging to the plurality of divided control function groups, and outputting each result of the operation processing to the plurality of corresponding I/O processing units within the control function group; and the I/O processing units are connected to the operation processing units by one communication unit, and information between the I/O processing units and the operation processing units is transmitted and received via this communication unit.
In the present invention, a scheduler adjusts schedules for transmit-receive of information between the plurality of I/O processing units and the plurality of operation processing units to make the system execute efficient communication processing.
In the present invention, a scheduler is provided in any of the plurality of operation processing units to make any of the plurality of operation processing units execute scheduling by the scheduler.
In the present invention, each of I/O processing units and operation control units has at least normal mode to shift to a status of a normal processing operation and maintenance mode to shift to a status of system maintenance, and a scheduler monitors the status of transmission by the plurality of I/O processing units and the plurality of operation processing units, transmits an alarm message using the communication unit to the plurality of I/O processing units and the plurality of operation processing units when any abnormal condition is detected, and shifts the plurality of I/O processing units and the plurality of operation processing units from the normal mode to the maintenance mode to prevent runaway or the like of the I/O processing units and operation processing units before it happens.
In the present invention, a format of information to be transmitted and received by the first communication unit, second communication unit, and the communication unit is made common by using a standardized information format.
In the present invention, each of I/O processing units and operation processing units further comprises an identifying unit, which adds identifying information specific to the vehicle-control communication system to information to be transmitted via the first communication unit, second communication unit, and the communication unit, transmits the information, and also performs identification of received information.
In the present invention, each of I/O processing units and operation processing units further comprises an encrypting/decrypting unit, which encrypts information to be transmitted via the first communication unit, second communication unit, and the communication unit using an encryption key, and decrypts the encrypted information.
Other objects and features of this invention will become apparent from the following description with reference to the accompanying drawings.